Lay-up method of composite aircraft parts comprising an opening

Abstract

A lay-up method of composite aircraft parts with an opening. Composite tows having an orientation of 0°, 90° or +/−45° are laid up forming plies which form a composite laminate. Each tow having an orientation of 0° and being within the perimeter of the opening comprises: a first gap located at approximately ⅗ of the length of the first semi-major axis from the center, the first gap being configured as a first elongated gap longitudinally perpendicular to the orientation of the tow, and a second gap located at approximately ⅗ of the length of the second semi-major axis from the center, the second gap being configured as a second elongated gap longitudinally perpendicular to the orientation of the tow.

Claimed is: 
     
         1 . A lay-up method of composite aircraft parts comprising an opening, the opening comprising a perimeter, a major axis, a minor axis, a center, and a first semi-major axis and a second semi-major axis both departing from the center, the lay-up method comprising the steps of:
 laying-up a plurality of composite tows having an orientation of 0°, 90° or +/−45° forming plies which in turn form a composite laminate,   wherein the composite tows having an orientation of 0° are parallel to the major axis of the opening,   wherein each composite tow having an orientation of 0° and being within the perimeter of the opening comprises:
 a first gap located at approximately ⅗ of the length of the first semi-major axis from the center, the first gap being configured as a first elongated gap longitudinally perpendicular to the orientation of the composite tow, and 
 a second gap located at approximately ⅗ of a length of the second semi-major axis from the center, the second gap being configured as a second elongated gap longitudinally perpendicular to the orientation of the composite tow. 
   
     
     
         2 . The lay-up method according to  claim 1 , further comprising the following steps:
 laying-up a composite tow having an orientation of 0° until approximately ⅗ of the first semi-major axis of the opening from the center,   cutting the laid-up composite tow at approximately ⅗ of the first semi-major axis of the opening perpendicular to the orientation of the composite tow,   leaving the first gap and continuing the lay-up of the composite tow until approximately ⅗ of the second semi-major axis of the opening from the center,   cutting the laid-up composite tow at approximately ⅗ of the second semi-major axis of the opening perpendicular to the orientation of the composite tow,   leaving the second gap and continuing the lay-up of the composite tow,   repeating the above steps with at least one or more composite tows having an orientation of 0° and located within the perimeter of the opening.   
     
     
         3 . The lay-up method according to  claim 1 , wherein tows having an orientation of +/−45° and being within the perimeter of the opening comprise:
 the first gap located at approximately ⅗ of a length of the first semi-major axis from the center, the first gap being configured as a first elongated gap longitudinally perpendicular to the orientation of the composite tow; or 
 the second gap located at approximately ⅗ of a length of the second semi-major axis from the center, the second gap being configured as a second elongated gap longitudinally perpendicular to the orientation of the composite tow; or 
 both. 
 
     
     
         4 . The lay-up method according to  claim 3 , wherein the method further comprises the following steps:
 laying-up a composite tow having an orientation of +/−45°,   when the composite tow crosses a first line located approximately at ⅗ of the first semi-major axis of the opening from the center, cutting the laid-up composite tow at approximately ⅗ of the first semi-major axis of the opening perpendicular to the orientation of the tow,   leaving the first gap and continuing the lay-up of the composite tow,   when the composite tow crosses a second line located approximately at ⅗ of the second semi-major axis of the opening from the center cutting the laid-up composite tow at approximately ⅗ of the second semi-major axis of the opening from the center perpendicular to the orientation of the tow,   leaving the second gap and continuing the lay-up of the tow.   
     
     
         5 . The lay-up method according to  claim 1 , wherein in a first step the composite tows are laid-up to form the laminate and in a second step a cut of a thickness of the laminate is performed at approximately ⅗ of the first and the second semi-major axis of the opening from the center to form the first and the second gaps as a first and a second elongated gap longitudinally perpendicular to the tows having an orientation of 0°. 
     
     
         6 . The lay-up method according to  claim 1 , wherein the first gap and the second gap are located in a range of ⅗ of a length of the first and the semi-major axis from the center +/−a width of the composite tow. 
     
     
         7 . The lay-up method according to  claim 1 , wherein a width in the direction parallel to the orientation of the composite tow of the first and the second gaps is between 1.5 mm and 2 mm. 
     
     
         8 . The lay-up method according to  claim 1 , wherein the major axis and the minor axis of the opening have the same length. 
     
     
         9 . The lay-up method according to  claim 1 , wherein a laminate tows width is greater than 12.7 mm. 
     
     
         10 . The lay-up method according to  claim 1 , wherein the aircraft part is a wing or a horizontal tail plane (HTP).